During the install of LMDE2, I selected the English language for the install, then went to select (en-US) locale, picked Belgium as my location and keyboard layout. But when I reached the screen for partitioning and format, the language of the program suddenly went in German, while the rest of the install was in English. So not a critical bug, but a bug nonetheless. I've seen this bug on early version of Raspbian and Ubuntu Mate for Raspberry Pi.
The last "sign" of this bug appeared in the first login screen after the install. If I wanted to change the keyboard layout there, I would still be given the choice between US keyboard or a German Belgian keyboard layout instead of just the US. I would guess this problem is the continuation of the bug described above.
I tested this with the latest LMDE2 image given from the website (June 2017).